My room size is ~20 x 24 although home theatre footprint within this room will be ~14 x 14. I have an Onkyo TX-NR709 Receiver rated at 90W per channel. I would like to know if a supercinema 50 system will"fill" this room appropriately? Also is a second FF4 sub suggested for a room this size?

would greatly appreciate any advice from the forum.

I'll start, but forum members should certainly offer up their thoughts.

Setup properly, yes, since most of the hard work will be done by the subwoofer(s). The subject of multiple subs is complex, but generally two subs is always better then one. In the case of a Satellite/Sub system like the SuperCinema 50, two subs located int the front (or even front center) of the room yields the best and most consistent overall results.

My room is setup fairly similar - it's 13' x 18', but the theater footprint is about 12' x 13'. That sized space doesn't require two subs, so you should be able to get away with just one if need be. That said - the addition of a second sub substantially increases the listening experience. I'd see if a local dealer would let you borrow a second sub overnight to try the setup out. (mine did, after a minor deposit).

I'm going to defer commenting on the receiver, but if the Onkyo puts out 90 quality watts per channel, you'll be fine matching it with a SS50 cinema speaker system.

As far as filling the room - the short answer is "absolutely". I was very concerned initially, because I heard a SS50 cinema system with the SS50s placed very close together (6' apart). This made things sound small and unappealing. I was able to demo some SS3's at home and spread them out, which really allowed them to show what they can do.

I've been running my SS50 cinema system for about 8 months now, and I'm still very, very happy with it (I do have two subs). It has no problem filling the space, and I get a lot of comments from friends who think that it sounds much better than a movie-theater setup (better sound, smaller space, wider sound spectrum, etc).

If you can find a local dealer who'll let you demo a system overnight, do so. It's the truest test of how the speakers will perform for you. That, and you'll get to hear those magical HVFR tweeters in your own home!

Thx for the great feedback!